ACTG 320 was a clinical trial of anti-HIV medications which compared the use of a three drug combination Zidovudine (ZDV)+Indinavir (IDV) to a two drug combina-tion (ZDV + 3TC), in persons who had previously taken Zidovudine ZDV. The three drug combination included two medications that were potent and new, as compared to the two drug combination which had only one new drug. This study showed that the three drug combination was more effective. The current study is designed to provide at least two new and potent antiretrovirals to persons who have been taking ZDV or d4T and 3TC either as part of ACTG 320, as part of another study or as prescribed by their primary doctor.